Tuberculosis
New Generation Vaccines
Mark Hatherill Director, South African Tuberculosis Vaccine Initiative University of Cape Town
1 2 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials (recent results)
• Pending results and new trials
• Future priorities and questions
3 Courtesy Aeras, accessed 23 June 2018
4 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials (recent results)
• Pending results and new trials
• Future priorities and questions
5 Strategic Priority #1 PPC: New TB Vaccines for Use in Adolescents and Adults • INDICATION – Immunization for prevention of active pulmonary TB disease • TARGET POPULATION – Adolescents and adults. Proof of concept should prompt pediatric studies. • OUTCOME MEASURE AND EFFICACY – 50% or greater efficacy in preventing confirmed pulmonary TB – Protect both subjects with and without past Mtb infection – Protective in different geographical regions and latitudes • SAFETY – Safety should be favourable in particular risk groups, such as individuals living with HIV/AIDS
Courtesy Johan Vekemans; New TB Vaccine WHO Working Group 6 Impact of adult vs infant vaccination strategies
Adult vaccine strategy 40% Modeled impact of a new TB vaccine targeted at VE and 5-year protection infants (D) or adults (E) (E) greater impact on TB incidence than infant vaccine 80% VE and lifelong protection (D) by 2050
Adult vaccine likely to prevent more infant TB cases than an infant vaccine
– due to reduction in M.tb transmission
Knight, PNAS 2014 *waves = mass campaigns
7 Strategic Priority #2 PPC: New TB Vaccines for Use in Neonates and Infants • INDICATION – Prevention of TB, including severe, disseminated, meningitis and pulmonary TB, in infants and young children • OUTCOME MEASURE AND EFFICACY – Equal to or greater than 80% vaccine efficacy as compared to baseline incidence, or superior efficacy as compared to BCG • SAFETY – Improved safety as compared to current BCG – Demonstrated safety in HIV infected babies – Reduction of injection site swelling, pain, drainage, and scarring, and local lymphadenopathy would represent welcomed improvement over BCG
Courtesy Johan Vekemans; New TB Vaccine WHO Working Group 8 PPC: New TB Vaccines
• DURATION OF PROTECTION – Demonstrated efficacy ≥2 years for initial policy decision – ≥10 year protection after primary immunization
• IMMUNOGENICTY – Identification of a vaccine-induced immune correlate of protection – Conservation of biological specimens for future use
• SCHEDULE – ≤ 3 doses for primary immunization. – Booster dose(s) ≤ 5-10 years – Heterologous prime boost regimens after neonatal BCG considered
• CO-ADMINISTRATION – Favourable safety and immunologic non-interference
Courtesy Johan Vekemans; New TB Vaccine WHO Working Group 9 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials (recent results)
• Pending results and new trials
• Future priorities and questions
10 The Shift to the Left: NHP challenge model
Source: Bill & Melinda Gates Foundation
11 Rhesus CMV vectors 4 RhCMV vectors based on 68-1 RhCMV strain that together expressed 9 different Mtb proteins: ESAT-6, Ag85A, Ag85B, Rv3407, Rv1733, Rv2626, Rpf A, Rpf C and Rpf D
Intrabronchial challenge model rhesus macaques 1 year after first vaccination
RhCMV vaccination reduced extent of TB disease by 68% vs unvaccinated controls 14 of 34 (41%) showed no TB disease by CT or at necropsy vs 0 of 17 unvaccinated controls 10 Mtb-culture-negative for all tissues Potential challenges for entry into clinical trials Safety in humans Manufacture 12 Alternative Routes BCG Administration Intravenous high-dose BCG
Rhesus macaques, 6 per group
ID 2-8 x 105 cfu/mL BCG
IV 2-8 X 106 cfu/mL BCG
IT 2-8 X 107 cfu/mL BCG
Aerosol nebulized HD M.tuberculosis challenge
High dose IV BCG Improved lung/total pathology scores Improved survival Vs unvaccinated controls and ID BCG
Implementation and safety challenges Research tool or viable strategy? 13 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials – Prevention of M.tuberculosis infection (POI) – Prevention of Recurrent TB (POR)
• Pending results and new trials
• Future priorities and questions
14 Rationale for Prevention of Infection (POI) trials
Case -Control Studies Evidence that primary BCG vaccination provides modest protection against M.tb infection (IGRA conversion)
Meta-analysis of 14 retrospective case-control studies (n=3,855) BCG protective RR for MTB infection 0.81 (95% CI 0.71 - 0.92) Mtb infection occurs >10x rate TB disease Roy BMJ 2014 Smaller, less costly proof of concept POI efficacy trials Opportunity to discover immune correlates of protection Long-term impact on TB disease (POD)?
15 Randomized controlled trial to evaluate safety, immunogenicity, and prevention of initial and/or sustained QuantiFERON-TB Gold In-tube (QFT) conversion by H4:IC31 or BCG revaccination
n=990 healthy, HIV-uninfected, QFT-negative, SA adolescents (12-17 years) BCG vaccinated in infancy No previous TB disease or household TB contact
3 arms, randomized 1:1:1 Double-blind intramuscular injection (D0 and D56) saline placebo OR H4:IC31® OR Open-label intradermal injection (D0) BCG Vaccine (Statens Serum Institut) (2-8 x 105 CFU)
H4 (Sanofi Pasteur) subunit vaccine (mycobacterial antigens Ag85B, TB10.4) (not in QFT)
Ag85B: expressed by both M.tb and BCG, mycolyl transferase TB10.4: expressed by both M.tb and BCG, secreted protein (same family as ESAT-6)
Follow-up 2 years: serial 6-monthly QFT testing (QFT tests antigens ESAT-6/CFP-10/TB-7.7)
Primary endpoint: initial QFT conversion negative positive Secondary endpoint: sustained QFT conversion negative positive (6m)
16
Placebo n = 49/310 (16%) 10 Placebo Efficacy Primary Endpoint
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Study month Placebo17 H4:IC31 BCG QFT Reversion (n=47; 37%)
Placebo 12/48 (25.0%) H4:IC31 17/42 (40.5%) BCG 18/39 (46.2%)
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18 Efficacy Secondary Endpoint: Sustained QFT conversion (n=82; 63%)
Placebo H4:IC31 BCG
n=25 10 n=36 10 10 n=21
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Placebo 36/310 11.6% H4:IC31 25/308 8.1% BCG 21/312 6.7%
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A 312 308 297 281 136 -20 Placebo H4:IC31 BCG H4:IC31 BCG 19 Impact of POI Trial results
1) Evidence POI design can detect vaccine efficacy in high M.tb transmission setting
- identified sustained QFT conversion as suitable endpoint - POI needs validation as tool for vaccine up-selection in future POD trial
2) Modest H4:IC31 signal, suggests biological effect
- first indication of protection against M.tb in humans by novel subunit vaccine
3) Convincing BCG revaccination efficacy signal - allow search for immune correlates of protection (M.tb infection) - justifies (re)evaluation of BCG revaccination for POD in M.tb-uninfected persons
20 Dar-901 POI
DAR-901 TB Booster Vaccine to Prevent TB in Adolescents (DAR-PIA)
Vaccine 3-dose ID DAR901 (inactivated whole cell M.obuense) Sponsor Dartmouth Population n=650 IGRA- adolescents Endpoints IGRA conversion Site/s Tanzania
21 H56:IC31 POR
A Phase 2, Double-blind, Randomized, Placebo-Controlled Study to Evaluate Prevention of Recurrence (POR)
Vaccine 2-dose IM H56:IC31(fusion protein Ag85B; ESAT-6 and Rv2660c) Sponsor Sponsor Aeras (SSI) Population 900 Rx cured TB patients Endpoints TB recurrence (confirmed) 12 months Site/s South Africa, Tanzania
PENDING: POI - Adolescents
22 ID93 POR
Phase 2a ID93 + GLA-SE Vaccine Trial in TB Patients After Treatment Completion
Vaccine 2-dose IM ID93 + GLA-SE (fusion protein virulence Rv2608, Rv3619, Rv3620; & latency Rv1813 antigens) Sponsor IDRI Population N=60 Rx cured TB patients Endpoints Safety and immunogenicity Site/s South Africa
23 VPM1002 POR
Study to Check the Efficacy and Safety of Recombinant BCG Vaccine in Prevention of TB Recurrence in India
Vaccine single-dose ID VPM1002 (live recombinant BCG) Sponsor SII Population 2,000 Rx cured TB patients Endpoints Safety & TB recurrence (12 months) Site/s India
PENDING: POD – Household contacts (+MIP) POD -- Infants
24 Challenges for live mycobacterial vaccines
BCG efficacy is variable Average RR 0.5 (0.35 – 0.72)
Highest BCG protection against TB disease in infants, and Mtb-uninfected children (RR 0.26), compared to Mtb-infected and - uninfected adults (RR 0.88)
Implications for efficacy of new live mycobacterial vaccines in high TB burden countries where >40% adults are Mtb- infected (Mtb-exposed/household contact designs; POR)
Meta-analysis, Mangtani CID 2014
25 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials
• Pending results and new trials
• Future priorities and questions
26 MTBVAC Phase 1 infants
Dose-escalation Safety and Immunogenicity Study to Compare MTBVAC to BCG in Newborns With a Safety Arm in Adults Vaccine Single dose ID MTBVAC (live attenuated Mtb) Sponsor Biofabri Population 18 BCG+ adults 36 BCG- infants Endpoints Safety, immunogenicity PENDING Site/s South Africa Phase 2a SA infants Phase 2a SA adults 27 Potential interference with diagnostic tests for M.tb infection
BCG False+ tuberculin skin test (TST) IGRA tests Mtb antigens ESAT-6/CFP-10/TB-7.7 (not present in BCG)
Vaccines containing ESAT-6 (eg. H56:IC31) and CFP- 10 (eg. MTBVAC) may affect IGRA readout
Frequency, magnitude, duration? Vaccine development vs test development
Challenge for implementation in populations where test for Mtb infection is indication for preventive therapy eg. Children (NCT02729571)
Early post-vaccination IGRA ESAT-6-free IGRA CFP-10-free IGRA WBA peptide pool
28 M.Vaccae POD
Phase III Clinical Study of Efficacy and Safety of Vaccae™ to Prevent Tuberculosis
Vaccine 6-dose IM M.vaccae (inactivated whole cell) Sponsor Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. Population 10,000 Mtb infected (TST+) adults Endpoints TB disease Site/s China
Results awaited…
29 M72/ASO1E POD
Study to Evaluate the Efficacy of GlaxoSmithKline (GSK) Biologicals' Candidate Tuberculosis (TB) Vaccine in Adults
Vaccine 2-dose IM M72/ASO1E (fusion protein Mtb32A, Mtb39A) Sponsor GSK (Aeras) Population 3,500 IGRA+ adults Endpoints Incident TB disease (confirmed), 36 months Site/s South Africa, Kenya, Zambia
Results awaited September 2018
30 • TB vaccine pipeline update
• Preferred Product Characteristics (New TB Vaccine WHO Working Group)
• Non-human primate data
• Proof of concept trials
• Pending results and new trials
• Future priorities and questions
31 Strategies for Protection of M.tb-infected and M.tb–uninfected Populations
Estimated 23% global population M.tb-infected
High TB incidence countries >40%
Houben, PloS Medicine 2016
TB disease incidence rises rapidly from adolescence
Mahomed IJTLD 2011 Wood SAMJ 2010
Implications for optimal age of vaccination/s
32 Strategies for Protection of M.tb-infected and M.tb–uninfected Populations
BCG revaccination POI efficacy signal requires validation in POD trial among Mtb-uninfected populations (77%) - durability - high vs low TB transmission/M.tb infection prevalence - geography/genetic background
Target population younger adolescents?
Pending results from POD efficacy trials among Mtb-infected populations (23%)
Target population older adolescents/adults?
Key strategy questions: Optimal age of vaccination/s? Single vaccine? Homologous prime and boost? Heterologous prime and boost?
33 changes in TB vaccine R & D stakeholder landscape
Funding commitment to new TB vaccine development by European & Developing Country Clinical Trials Partnership (EDCTP) – 2017
Moscow Global Ministerial Conference on Ending TB Establishment of BRICS Tuberculosis Research Network – 2017
UN General Assembly High-level Meeting on Ending TB – 2018
Establishment of Gates Medical Research Institute – 2018
Limited global capacity for large TB vaccine efficacy trials
Organizational/operational and trial site capacity
Lack of business incentive for late stage development
Dependent on small group of non-industry funders
Need to widen funding acess
34